We have isolated the mRNAs coding for alpha and beta tubulin from embryonic chick brain. By the sequential use of reverse transcriptase, DNA polymerase I, and S1 nuclease, we propose to make synthetic tubulin genes. The number of tubulin genes in the chick genome will be determined by DNA-DNA reassociation kinetics. Fragment maps of the synthetic genes will be prepared with restriction endonucleases. The base sequences of the coding and non-coding regions of alpha and beta tubulin will be determined with rapid DNA sequencing techniques.